While some in Labour fear entryism and the spectre of Militant, within Momentum itself there are tensions and contradictions that may yet explode

Depending on who you listen to, Momentum is either the cutting edge of 21st century progressive activism, or a Corbynite conspiracy to take over the Labour party, eject any errant MPs, and commence the age of copper-bottomed British socialism, following the new leader’s example.

According to its online blurb, the group is intended to be “a network of people and organisations that will continue the energy and enthusiasm of Jeremy’s campaign”. There are 150,000 names on its email list. It has four full-time staff and pledges of funding from trade unions. Branches are forming all over the country; exactly what they will do, and how they may or may not connect with the Labour party, are currently matters of discussion and debate. But after the torrid events of recent weeks – the Labour split on Syria, endless explosions of nastiness, and all that talk of deselecting “pro-war” MPs – certain people’s understanding of what Momentum is up to now drips with disdain and fear.